Maybe I'm wrong about this, but there's a spot in the movie where Obi-Wan has a minor duel with Darth Maul in the middle of the last fight. Why did Qui-Gon leave the scene? Well, if you look closely, just before this scene, Obi-wan and Qui-Gon are both fighting Maul and Obi HITS Qui-Gon with his light saber! Through the rest of the movie up till he dies, his foot is fine. Jedi healing powers? Or one bad screw-up?